1. Field of the Invention
The present invention relates to a method of manufacturing an ink jet recording head for discharging liquid droplets to perform recording, an ink jet recording head, and an ink jet cartridge, concretely to a method of manufacturing an ink jet recording head comprising a filter, an ink jet recording head, and an ink jet cartridge.
2. Related Background Art
In recent years, to miniaturize an ink jet recording head, and raising a density of heads, a method has been proposed in which an electric control circuit for driving an ink discharge pressure generation element is built in a substrate using a semiconductor manufacturing technique. In order to supply ink to a plurality of discharge ports, the ink jet recording head is structured such that nozzles are passed through the substrate from the back surface of the substrate, and connected to a common ink supply port, and the ink is supplied to the respective nozzles from the common ink supply port. With regard to the recording head, a method described in U.S. Pat. No. 5,478,606 has been known as a method of manufacturing the head with a remarkably high precision, in which a distance between the ink discharge pressure generation element for discharging the ink from the discharge ports, and the discharge ports is reduced. When a silicon substrate is used as the substrate of the ink jet recording head, as described in U.S. Pat. No. 6,139,761, it is possible to form the ink supply port using an anisotropic etching technique.
As the reliability demanded for the ink jet recording head, dust and foreign matters are inhibited from being introduced into the nozzles. As a considered cause, the dust or foreign matters are mixed into the nozzles in the process of manufacturing the ink jet recording head, or the dust or foreign matters are sent together with the ink and enter the nozzles. As a countermeasure against this problem, it has been known that a filter is disposed on the ink jet recording head.
For example, in U.S. Pat. No. 6,264,309, it has been described that a resistance material layer for etching the ink supply port is disposed on the surface provided with a heater, and a plurality of holes are disposed in the resistance material layer to form the ink supply ports and also the filter in the recording head constituted of lamination of members for forming the discharge ports and channels with respect to the silicon substrate provided with the ink supply port. In U.S. Pat. No. 6,543,884, a constitution has been described in which individual ink supply ports are disposed for a plurality of ink jet chambers.
On the other hand, in Japanese Patent Application Laid-Open No. 2000-94700, it has been described that when the ink supply port is formed in the silicon substrate, a membrane filter is disposed simultaneously with the ink supply port using side etching with respect to an etching-proof mask disposed on a side opposite to a side on which a heater is disposed.
However, in the U.S. Pat. Nos. 6,264,309 and 6,543,884, there is a fear that the dust or foreign matters are mixed into the nozzles during lamination in the constitution in which the members for forming the discharge ports and channels are laminated with respect to the silicon substrate provided with the ink supply port. In the method in which the holes are disposed in the thin film on the silicon substrate constituting the filter before the ink supply port is formed in the silicon substrate as described in these documents, the ink supply port is formed in a state in which the holes are made in a layer for stopping anisotropic etching, described in the U.S. Pat. No. 6,139,761. Therefore, when the method described in the above-described document is to be applied to the method described in the U.S. Pat. No. 5,478,606, a soluble resin for forming the channels is immersed in an etching solution for forming the ink supply port, and there is a possibility that precision of the manufactured head, or yield of high-precision head manufacturing is adversely affected.
On the other hand, in the method of the Japanese Patent Application Laid-Open No. 2000-94700, an insulating film formed of SiO2, SiN or the like is used as the etching-proof mask, but the insulating film (etching-proof mask) exposed on the back surface of the silicon substrate is usually constituted as a deposited film formed by sputtering or chemical vapor development. The film is exposed in various solutions in subsequently performed steps and corroded, or finely damaged during conveyance in a semiconductor manufacturing apparatus during a manufacturing process in some case. Therefore, it has been very difficult to keep the filter by the insulating film without any defect until a final product is manufactured.